Small cold storage installation and debugging technology below 100 tons

Small cold storage installation and debugging technology below 100 tons

1. Check if the temperature sensor package is intact before installation;

2. The installation position of the expansion valve must be close to the evaporator. The valve body should be installed vertically and cannot be tilted or inverted.

3, the installation should pay attention to keep the liquid in the temperature sensor bag always in the temperature sensor package, so the temperature sensor package should be installed lower than the valve body;

4, the temperature sensor package should be installed on the outlet level of the evaporator as much as possible, generally should be more than 1.5M away from the compressor suction port

5, the temperature sensor can not be installed on the return pipe with effusion;

6. If the evaporator outlet has a gas-liquid exchanger, the temperature is generally packaged at the outlet of the evaporator, ie before the heat exchanger;

7. The temperature sensing package is usually placed on the evaporator return pipe and tightly attached to the pipe wall, and the contact area should be cleaned;

8. When the diameter of the return pipe is less than 25MM, the temperature package can be tied at the top of the return pipe; when the diameter is larger than 25MM, it can be tied at 45° of the lower side of the return pipe to prevent the oil at the bottom of the pipe from affecting the temperature package. Temperature effect.

Second, the expansion valve debugging technology 100 tons of small cold storage installation and commissioning technology

1. The evaporator outlet should use the thermometer to measure the temperature or look at the suction pressure to check the superheat;

2. The expansion valve adjusts the superheat degree to be too small (the liquid supply amount is too large), and the adjustment rod should rotate half a turn or one turn in the clockwise direction (that is, increase the spring force and reduce the valve opening degree) to reduce the refrigerant flow rate; The number of turns of the thread at one time should not be too much (the adjustment rod thread rotates one turn, and the degree of superheat changes by about 1-2°).

3. Expansion valve adjustment experience: Turn the adjustment rod thread to change the opening degree of the valve, so that the evaporator can just be frosted or dew condensation outside the return pipe. For a refrigerating device with an evaporation temperature lower than 0 degrees, if it is touched by hand after frosting, there is a feeling of coldness that sticks the hand, and the opening degree is appropriate; for the evaporation temperature above 0 degrees, the condensation is visible. Judgment of the situation.

4. The correct debugging of the expansion valve directly affects the cooling effect and energy saving of the cold storage. The cooling of the cold storage is slow, and the expansion valve is improperly adjusted. According to the thermal properties of the refrigerant, the lower the pressure, the lower the corresponding temperature; the higher the pressure, the higher the corresponding temperature. The adjustment of the expansion valve is the key to Zui. The opening degree of the expansion valve is small, the flow rate of the refrigerant is small, and the pressure is low; the opening degree of the expansion valve is large, the flow rate of the refrigerant is high, and the pressure is high.

Third, expansion valve debugging precautions

If the expansion valve outlet pressure is too low, the corresponding evaporation pressure and temperature are too low. However, due to the decrease in the flow rate into the evaporator, the pressure is reduced, the evaporation rate is slowed down, the cooling capacity per unit volume (time) is decreased, and the cooling efficiency is lowered. Conversely, if the expansion valve outlet pressure is too high, the corresponding evaporation pressure and temperature are too high. The flow rate and pressure entering the evaporator are increased. Due to the excess evaporation of the liquid, the over-exhausted gas (or even the liquid) is sucked by the compressor, causing the wet stroke (liquid blow) of the compressor, causing the compressor to malfunction, resulting in a series of work. Bad conditions, even damage the compressor. Therefore, the opening degree of the expansion valve should be adjusted according to the library temperature at that time, that is, adjusted under the pressure corresponding to the reservoir temperature. Small cold storage installation and debugging technology below 100 tons

The expansion valve must be carefully and patiently adjusted. The pressure must be exchanged between the evaporator and the reservoir to create a heat exchange boiling (evaporation) and then through the pipeline into the compressor suction chamber to reflect the pressure gauge. It takes a time. Each time the expansion valve is mobilized, it usually takes 10~15 minutes before the adjustment pressure of the expansion valve can be stabilized on the suction pressure gauge, and the adjustment cannot be rushed.

The suction pressure of the compressor is the main parameter for adjusting the pressure of the expansion valve. It is often prone to failures such as clogging of the filter screen and leakage of the temperature sensitive agent. The adjustment reaction is not sensitive, the regulation is out of control or cannot be adjusted. When frost is formed at the inlet of the expansion valve (or the valve cover is also frosted), the temperature of the inlet pipe is lower than normal temperature and even condensation; the suction pressure of the compressor is lower than the corresponding pressure at the storage temperature, the machine operating temperature And the exhaust temperature is high, the cooling temperature drops slowly or can not fall, mostly the filter screen of the expansion valve is blocked, or the dirty plug is blocked.